Push to talk oddities

[Ranera]

I have a whisper/shout bind set to Num Lock, and my normal PTT is on Caps Lock.

I run Ventrilo at the same time (two different groups of people) and that PTT is set to Pause.

For some reason, when I press Pause, Mumble uses it as my whisper/shout (as well as num lock) despite the fact that Pause is not assigned to anything in my shortcuts.

However, it only does this when Mumble is in the background. If I click on the mumble window or am doing anything in it, Pause has no effect. As soon as I click to another window (game, browser, folder, etc) Pause becomes my whisper/shout PTT again.

How do I fix this?